The invention relates generally to hand-held production tools and more specifically to such tools denominated blade wrenches which include a slender, arm-like structure having a power driven fastener engaging means adjacent its terminus.
Air and electrically powered hand-held production tools are indispensable components of high speed modern production lines such as are utilized in the automotive industry. In addition to their obvious advantages of speed and reduced operator fatigue, a major reason for their acceptance has been their adaptability to a multitude of production and assembly tasks. Specifically, torque indicating and limiting air powered fastener wrenches, tools for seating and permanently crimping fasteners, hog ringers for securing metal rings and clamps and reaction bar tools which prevent the reaction torque of a fastening operation from being transmitted to the tool operator are all representative of this adaptability.
The blade wrench is likewise a result of this adaptability and was developed in response to the requirement of tightening threaded fasteners in assembly locations where access and clearance along the axis of the fastener were limited. The blade wrench includes a conventional hand tool power train such as an electric or air driven motor and gear reduction unit. The output of the gear reduction unit drives a socket or other suitable fastener engaging means disposed within a thin, blade-like extension through a plurality of aligned idler gears. The socket rotates about an axis normal to the blade-like portion.
Typically, the thickness of the blade portion may be from three-quarters to seven-eighths of an inch and it thus may engage a bolt head spaced axially little more than this distance from an adjacent obstruction or be used to secure a nut to a captive bolt where the axial clearance between the end of the bolt and an adjacent obstruction is only slighter greater than the thickness of the wrench blade. The advantages of a blade wrench are particularly apparent in automotive production line use wherein clearances between seats and floors, door panels, fender wells, and the like may preclude utilization of conventional right-angle head pneumatic tools.
In the prior art, the blade portion of the blade wrench is rigidly secured to the tool body and extends along and is aligned with the axis thereof. Such an alignment facilitates positioning and engagement of the socket with the fastener by providing aligned visual reference points. In many specific fastening operations, however, the alignment of the blade portion and tool body poses problems which may render the tool either difficult or impossible to use. For example, such an alignment obviously maximizes the length of the tool and may cause interference with objects and structures at radial distances from the fastening less than the length of the tool. A more serious problem arises when the fastener to be manipulated is disposed in a blind, angled passage or in a location adjacent both axial and radial obstructions.